Bloom and wither

You invoke both death and life upon a 10-foot-radius sphere centered on a point within range. Each creature of your choice in that area must make a Constitution saving throw, taking 2d6 necrotic damage on a failed save, or half as much damage on a successful one. Nonmagical vegetation in that area withers.

In addition, one creature of your choice in that area can spend and roll one of its unspent Hit Dice and regain a number of hit points equal to the roll plus your spellcasting ability modifier.